Objective To define the optimal intensity of oral anticoagulant therapy in patients with mechanical heart valve prostheses in Chongqing.  Methods All the 133 patients who had undergone valve replacement in our hospital were involved in this study. Warfarin therapy at an initial dose of 2.5 mg began when drainage tube was removed 24 or 48 h after operation. After oral anticoagulant therapy for 3 months

the relationship between the intensity of anticoagulant effect and dose of warfrain were analyzed. Then the optimal intensity of anticoagulant effect for the patients in Chongqing was defined.  Results The final mean value of international normalized ratio (INR) was (1.80±0.46)

and the mean dose of Warfain was recommended as (2.69±1.02) mg daily.  Conclusion INR for aortic valve replacement (AVR) patients is 1.65 (1.5-20)

for MVR patients is 1.87 (1.6-2.3)

for DVR patients is 1.65 (1.6-2.3)

for MVR and CABG patients is 1.94 (1.6-2.3)

and for Bentall patients is 1.86 (1.8-2.5). The optimal intensity of anticoagulant effect for the patients in Chongqing with mechanical heart valve prostheses is INR from 1.5 to 2.5

which could prevent thrombolic events and reduce the incidence of hemorrhagic events.